727 research outputs found
The Senegalese Sole Mx gene promoter contains a variable microsatellite region involved in the transcriptional
Interferons (IFNs) play a key role against viral infections by stimulating the expression of IFN stimulated genes, such as Mx. The transcriptional regulation of these genes in fish are poorly understood. The sequencing of the Senegalese sole (Solea senegalensis) Mx gene promoter revealed the presence of a guanosine-citosine rich region that contains a microsatellite, sited close to the translation start codon. The aim of the current study has been to determine the functional role of this region and to study its variability.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
The use of Polystyrene from Ballpen Barrels and Wood Ash as Additives in Making Lightweight Bricks.
This study aimed to determine the ability of polystyrene in ballpen barrels of making a brick to be more compacted than the ordinary clay bricks. Polystyrene is a synthetic aromatic hydrocarbon polymer made from the monomer styrene that also makes a brick denser. The Wood ash from burned wood are usually used by the gardeners as a good source of potash. Wood ash has an ability of making the bricks lighter than the usual clay bricks. Additional wood ash is better than coal ash, because coal ash has a dangerous chemicals that may harm human. The goal of this study is to lessen the ballpen barrels and wood ash that are not disposed properly and make this in a creative way. Five test was conducted to determine the potential of polystyrene and wood ash namely water absorption test, drop test, efflorescence test, compressive test and heat resistance test. Based from the data gathered, it concluded that polystyrene from ballpen barrel and wood ash with the ratio of 50% Cement, 25% Wood Ash, 25% Ballpen Barrels is effective additives in production of lightweigh
The CARMENES search for exoplanets around M dwarfs - Photospheric parameters of target stars from high-resolution spectroscopy
The new CARMENES instrument comprises two high-resolution and high-stability
spectrographs that are used to search for habitable planets around M dwarfs in
the visible and near-infrared regime via the Doppler technique. Characterising
our target sample is important for constraining the physical properties of any
planetary systems that are detected. The aim of this paper is to determine the
fundamental stellar parameters of the CARMENES M-dwarf target sample from
high-resolution spectra observed with CARMENES. We also include several M-dwarf
spectra observed with other high-resolution spectrographs, that is CAFE, FEROS,
and HRS, for completeness. We used a {chi}^2 method to derive the stellar
parameters effective temperature T_eff, surface gravity log g, and metallicity
[Fe/H] of the target stars by fitting the most recent version of the
PHOENIX-ACES models to high-resolution spectroscopic data. These stellar
atmosphere models incorporate a new equation of state to describe spectral
features of low-temperature stellar atmospheres. Since T_eff, log g, and [Fe/H]
show degeneracies, the surface gravity is determined independently using
stellar evolutionary models. We derive the stellar parameters for a total of
300 stars. The fits achieve very good agreement between the PHOENIX models and
observed spectra. We estimate that our method provides parameters with
uncertainties of {sigma} T_eff = 51 K, {sigma} log g = 0.07, and {sigma} [Fe/H]
= 0.16, and show that atmosphere models for low-mass stars have significantly
improved in the last years. Our work also provides an independent test of the
new PHOENIX-ACES models, and a comparison for other methods using
low-resolution spectra. In particular, our effective temperatures agree well
with literature values, while metallicities determined with our method exhibit
a larger spread when compared to literature results
Inhibition of Fungi and Gram-Negative Bacteria by Bacteriocin BacTN635 Produced by Lactobacillus plantarum sp. TN635
The aim of this study was to evaluate 54 lactic acid bacteria (LAB) strains isolated from meat, fermented vegetables and dairy products for their capacity to produce antimicrobial activities against several bacteria and fungi. The strain designed TN635 has been selected for advanced studies. The supernatant culture of this strain inhibits the growth of all tested pathogenic including the four Gram-negative bacteria (Salmonella enterica ATCC43972, Pseudomonas aeruginosa ATCC 49189, Hafnia sp. and Serratia sp.) and the pathogenic fungus Candida tropicalis R2 CIP203. Based on the nucleotide sequence of the 16S rRNA gene of the strain TN635 (1,540 pb accession no FN252881) and the phylogenetic analysis, we propose the assignment of our new isolate bacterium as Lactobacillus plantarum sp. TN635 strain. Its antimicrobial compound was determined as a proteinaceous substance, stable to heat and to treatment with surfactants and organic solvents. Highest antimicrobial activity was found between pH 3 and 11 with an optimum at pH = 7. The BacTN635 was purified to homogeneity by a four-step protocol involving ammonium sulfate precipitation, centrifugal microconcentrators with a 10-kDa membrane cutoff, gel filtration Sephadex G-25, and C18 reverse-phase HPLC. SDS-PAGE analysis of the purified BacTN635, revealed a single band with an estimated molecular mass of approximately 4 kDa. The maximum bacteriocin production (5,000 AU/ml) was recorded after a 16-h incubation in Man, Rogosa, and Sharpe (MRS) medium at 30 °C. The mode of action of the partial purified BacTN635 was identified as bactericidal against Listeria ivanovii BUG 496 and as fungistatic against C. tropicalis R2 CIP203
CARMENES input catalogue of M dwarfs IV. New rotation periods from photometric time series
Aims. The main goal of this work is to measure rotation periods of the M-type
dwarf stars being observed by the CARMENES exoplanet survey to help distinguish
radial-velocity signals produced by magnetic activity from those produced by
exoplanets. Rotation periods are also fundamental for a detailed study of the
relation between activity and rotation in late-type stars. Methods. We look for
significant periodic signals in 622 photometric time series of 337 bright,
nearby M dwarfs obtained by long-time baseline, automated surveys (MEarth,
ASAS, SuperWASP, NSVS, Catalina, ASAS-SN, K2, and HATNet) and for 20 stars
which we obtained with four 0.2-0.8 m telescopes at high geographical
latitudes. Results. We present 142 rotation periods (73 new) from 0.12 d to 133
d and ten long-term activity cycles (six new) from 3.0 a to 11.5 a. We compare
our determinations with those in the existing literature; we investigate the
distribution of P rot in the CARMENES input catalogue,the amplitude of
photometric variability, and their relation to vsin i and pEW(Halfa); and we
identify three very active stars with new rotation periods between 0.34 d and
23.6 d.Comment: 34 pages, 43 figures, 2 appendix table
Infrasound detection of approaching lahars
Infrasound may be used to detect the approach of hazardous volcanic mudflows, known as lahars, tens of minutes before their flow fronts arrive. We have analyzed signals from more than 20 secondary lahars caused by precipitation events at Fuego Volcano during Guatemala\u27s rainy season in May through October of 2022. We are able to quantify the capabilities of infrasound monitoring through comparison with seismic data, time lapse camera imagery, and high-resolution video of a well-recorded event on August 17. We determine that infrasound sensors, deployed adjacent to the lahar path and in small-aperture (10 s of meters) arrays, are particularly sensitive to remote detection of lahars, including small-sized events, at distances of at least 5 km. At Fuego Volcano these detections could be used to provide timely alerts of up to 30 min before lahars arrive at a downstream monitoring site, such as in the frequently impacted Ceniza drainage. We propose that continuous infrasound monitoring, from locations adjacent to a drainage, may complement seismic monitoring and serve as a valuable tool to help identify approaching hazards. On the other hand, infrasound arrays located a kilometer or more from the lahar path can be effectively used to track a lahar\u27s progression
Two close binaries across the hydrogen-burning limit in the Praesepe open cluster
We present Keck I/OSIRIS and Keck II/NIRC2 adaptive optics imaging of two
member candidates of the Praesepe stellar cluster (d=186.180.11 pc;
590-790 Myr), UGC J08451066+2148171 (L1.50.5) and UGCS J083019352003293
(no spectroscopic classification). We resolved UGCS J084510662148171 into a
binary system in the near-infrared, with a -band wavelength flux ratio of
0.890.04, a projected separation of 60.31.3 mas (11.20.7 au;
1). We also resolved UGCS J083019352003293 into a binary system with
a flux ratio of 0.460.03 and a separation of 62.50.9 mas. Assuming
zero eccentricity, we estimate minimum orbital periods of 100 years for
both systems. According to theoretical evolutionary models, we derive masses in
the range of 0.074-0.078 M and 0.072-0.076 M for the
primary and secondary of UGCS J084510662148171 for an age of 700100
Myr. In the case of UGCS J083019352003293, the primary is a low-mass star at
the stellar/substellar boundary (0.070-0.078 M) while the companion
candidate might be a brown dwarf (0.051-0.065 M). These are the first
two binaries composed of L dwarfs in Praesepe. They are benchmark systems to
derive the location of the substellar limit at the age and metallicity of
Praesepe, determine the age of the cluster based on the lithium depletion
boundary test, derive dynamical masses, and improve low-mass stellar and
substellar evolutionary models at a well-known age and metallicity.Comment: 12 pages, 5 figures, 3 tables, accepted for publication in MNRA
Non-Born-Oppenheimer calculations of the lowest vibrational energy of HD including relativistic corrections
In this work we report variational calculations of the two lowest vibrational states of the HD molecule within
the framework that does not assume the Born-Oppenheimer BO approximation. The nonrelativistic energies
of the states were corrected for the relativistic effects of the order of 2 where = 1
c , calculated as expectation
values of the operators representing these effects with the nonrelativistic non-BO wave functions. The non-BO
wave functions were expanded in terms of the one-center explicitly correlated Gaussian functions multiplied by
even powers of the internuclear distance. The v=0→1 transition energy obtained in the calculations is compared
with the previous calculations, as well as with the transition frequency obtained from the experimental
spectra. The comparison shows the need to include corrections higher than second order in to further
improve the agreement between the theory and the experimen
A Search for Very Low-mass Stars and Brown Dwarfs in the Young sigma Orionis Cluster
We present a CCD-based photometric survey covering 870 sq. arcmin in a young
stellar cluster around the young multiple star sigma Orionis. Our survey
limiting R, I, and Z magnitudes are 23.2, 21.8, and 21.0, respectively. From
our colour-magnitude diagrams, we have selected 49 faint objects, which
smoothly extrapolate the photometric sequence defined by more massive known
members. Adopting the currently accepted age interval of 2-10 Myr for the Orion
1b association and considering recent evolutionary models, our objects may span
a mass range from 0.1 down to 0.02 Msun, well within the substellar regime.
Follow-up low-resolution optical spectroscopy (635-920 nm) for eight of our
candidates (I=16-19.5) shows that they have spectral types M6-M8.5 which are
consistent with the expectations for true members. Compared with their Pleiades
counterparts of similar types, Halpha emission is generally stronger, while NaI
and KI absorption lines appear weaker, as expected for lower surface gravities
and younger ages. Additionally, TiO bands and in particular VO bands appear
clearly enhanced in our candidate with the latest spectral type, SOri 45 (M8.5,
I=19.5), compared to objects of similar types in older clusters and the field.
We have estimated the mass of this candidate at only 0.020-0.040 Msun, hence it
is one of the least massive brown dwarfs yet discovered. We also discuss in
this paper the potential role of deuterium as a tracer of both substellar
nature and age in very young clusters.Comment: Accepted for publication in ApJ Main Journal. 32 pages of text and
tables + 9 pages of figures. Figures 3a and 3b (gif format) provided
separatel
- …